The present invention relates to ionographic systems for creating images and, in particular, to the method and apparatus to control the vertical line width in such images in ionographic systems.
The problem of cross talk between adjacent electrodes in an ionographic print head is known. For example, U.S. Pat. No. 4,558,334 discloses a two electrode ion generator producing ions only during the print period requiring reduced power to achieve given ion outputs, and includes low impedance gated oscillators to reduce capacitive cross-talk between the electrodes.
In some ionographic systems, the problem of cross-talk manifests itself in the difficulty of producing vertical lines in created images. In such systems there is generally an array of adjacent modulating electrodes, each of the electrodes being driven by a gate receiving a strobe voltage and a data voltage to reproduce a black or white spot corresponding to a digital image. The cross-talk phenomenon, for example, is evidenced by vertical lines in the reproduced images that tend to start light and get darker as thy continue in the vertical direction until reaching a stable thickness and density. Also, the stable thickness is often too thin to the point that 1 bit vertical lines (lines of 1 bit or spot length) are virtually non-existent, and 2 bit vertical lines are approximately equal in width to a 1 bit horizontal line.
It is an object of the present invention, therefore, to provide a new and improved method and apparatus to control cross-talk in an ionographic printing device and in particular, to provide uniform and consistent vertical lines in images created by the ionographic printing device.
Further advantages of the present invention will become apparent as the following description proceeds, and the features characterizing the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.